Manually guided motor driven working device



Nov. 12, 1968 UEBEL MANUALLY GUIDED MOTOR DRIVEN WORKING DEVICE Filed Aug. 2, 1966 AGZ' I 0 WWW M i a;

United States Patent O 3,410,145 MANUALLY GUIDED MOTOR DRIVEN WORKING DEVICE Philipp Uebel, Munich, Germany, assignor to Hermann Wacker and Peter Wacker, Munich, Germany Filed Aug. 2, 1966, Ser. No. 569,738 Claims priority, application Germany, Sept. 7, 1965, W 39,860 6 Claims. (CI. 74-40) ABSTRACT OF THE DISCLOSURE Manually guided motor driven working device such as a tamper, having an adjustable rocking lever intermediate the drive motor and the swing or beat system which is supported at a fulcrum and adjustable by means of a pinion and toothed rack proximate the fulcrum of the lever.

BACKGROUND OF THE INVENTION The invention relates to earth compacting equipment such as tamping tools. More in particular, the invention concerns a manually guided motor driven working device with a reciprocating working tool.

In known devices of such construction the drive motor, which may be an electric motor or an internal combustion motor, is flanged onto the housing of the working device in a manner that it may be readily exchanged. The transmission of power from the drive motor to the recipro cating working tool is obtained, for example, by a coupling, a crank transmission and an intermediately connected swinging or beating system. Most commonly an internal combustion engine is used as the drive motor. The reason for that is that to satisfy the requirement of low structural height of the working device and thus easy manipulation of the device by the operator, the drive motor is provided with a suspended cylinder.

-It is understandable that it is not possible to utilize a diesel or four-cycle gasoline motor with this type of mounting of the drive motor, because with this type of motor it is necessary to have an oil sump for greasing or oiling the moving parts, but which is not dependable when the position of the apparatus is inclined by about 30.

The starting of a two-cycle motor having a suspended cylinder frequently involves problems or difiiculties, because the two-cycle mixture supplied to the internal combustion motor rapidy affects the spark plug and interrupts its function when the mixture is not ignited immediately, so that the engine readily dies, which in turn affects the operating economy.

A further shortcoming of apparatuses of known construction resides in that the crank transmission which is built in for the transmission of power between the coupling and the swing or beating system makes the drive motor dependent on a predetermined position of the crank transmission, because the crank shaft of the motor and the transmission shaft that picks up the power are supposed to be in alignment. If that is not the case, the crank transmission must be of large and heavy construction, which in turn results in the disadvantage of increased structural dimensions of the working device. Moreover, such a construction would introduce additional structural difficulties.

SUMMARY OF THE INVENTION It is an object of the invention to provide an operating device in which the shortcomings of the known devices are not inherent and which distinguishes itself by extremely short structural height accompanied by a favorable center of gravity and easy and repulsion free manipulation.

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In accordance with the invention this problem is solved in that for transmitting the power from the drive motor to the reciprocating tool a tilting or rocking lever is provided, which on the motor side is secured to a connecting rod and converts the rotary movement, for example of the crank shaft of an internal combustion motor, to reciprocating movement, and which at the operating side is secured to a connecting rod which moves the tool by way of a swing or beating system known per se.

One advantage of this form of construction according to the invention is seen in that the working device can be of extremely short form of construction. The high crank transmission that is known for devices of this type which incorporate a swing or beating system is eliminated. It is now possible to utilize as a drive motor also a diesel or four-cycle gasoline motor, because due to the relatively low mounting laterally alongside of the device, these motors can be arranged in normal position, i.e., with an upright cylinder. In addition the motor in accordance with the construction of power transmission provided with the invention is no longer dependent on a predetermined location and position on the device due to the elimination of the crank transmission, because it is possible with the tilting or rocking lever to bypass in any direction desired, and this provides for advantageous low position of the center of gravity for the entire working device which may be predetermined.

Furthermore, the use in accordance with the invention of a tilting or rocking lever as power transmitting component from the drive motor to the work tool makes possible repulsion-free or recoilless working. In tampers or hammers of known construction there necessarily occur back blows of the total mass of the working device which have to be intercepted by the operator, which results in rapid fatigue of the operator during the operation of such devices and necessitates expensive structural measures in order to soften the back blows or repercussions. In accordance with the invention this balancing of the mass is attained in that on the lever arm of the tilting or rocking lever on the motor side as well as also on the connecting rod secured to this lever arm, suitable masses are introduced.

A further advantage of the embodiment in accordance with the invention is afforded in that the lever arm defined by the connecting rod and the tilting or rocking lever can be changed in size. Applying this to practice means, for example, that in a tamper the stroke of the tamping tool can be adjusted at any time and thus adapted to the existing conditions of'the ground.

Such adjusting of the stroke can in accordance with the invention be obtained in a simple manner by manipulation but also automatically by a suitable device.

Further advantages and details of the invention will become apparent, from the following description with reference to an embodiment illustrated in the accompanying drawing, in which FIG. 1 shows, partly in section, an embodiment of the arrangement in accordance with the invention incorporated in a working device;

FIG. 2 is a partial view of the arrangement in accordance with the invention;

FIG. 3 is a section taken along line A-B in FIG. 2.

The drive motor 1 by way of its drive shaft 2 moves a motor connecting rod 3. The motor connecting rod is pivotally connected to the crank transmission of the motor at one end and at the other end it is pivotally connected to a tilting or rocking lever 4 which is journalled for pivotal movement about a fixed point or fulcrum 5. At the other end of the tilting or rocking lever a work side connecting rod 6 is provided which transmits the power from the motor 1 to the tool 8 by way of a swing or hearing system 7. This rod 6 has at its upper end a 3 pivotal connection with the rocking lever 4 and at its other end it is pivotally connected with the upper end of the swing system 7.

In order to obtain a most favorable balancing of the counteracting masses of the driven device 9 and the drive motor 1 the motor connecting rod 3 and the motor side of the tilting or rocking lever 4 are provided with additional weights 10. In order to change the magnitude of the lever arm of the tilting or rocking lever 4 defined by the motor connecting rod 3 and the lever on the motor side of the fixed point 5, the bore in the tilting or rocking lever 4 for journalling at point 5 is in the form of a slot 11. The displacement of the tilting or rocking lever 4 in the slot 11 may be effected by means ofa toothed rack 12 and a toothed gear 13 which engages the rack.

As shown in FIG. 3 the rocking lever is pivotally supported by the shaft 16 of a supporting member 15 in an aperture in the wall of the housing 14. The shaft of the pinion 13 extends from the housing, and a handle may be attached to the shaft 16 of the pinion by means of which the pinion 13 can be rotated in order to move the rocking lever 4 along the fixed point 5 presented by the supporting element 15.

The setting or adjusting can be undertaken either manually or automatically when the working device stands still or also during its operation.

Having now described my invention with reference to the embodiment illustrated in the drawing, I do not wish to be limited thereto, but what I desire to protect by Letters Patent of the United States is set forth in the appended claims.

Iclaim:

. 1. Manually guided motor driven working device with a reciprocable work tool mounted in a housing, a drive motor mounted on said housing and power transmission means extending between said drive motor and said reciprocable tool including a crank transmission on said motor and a swing or beat system in said housing, a rocking lever supported at a fulcrum, a motor connecting rod for converting rotary motion to reciprocating motion pivotally connected at one end to said crank transmission and pivotally connected at its other end to one end of the rocking lever on the motor side of the lever and a work side connecting rod pivotally connected at one end to said swing system and at the other end pivotally con nected to said rocking lever in a manner to impart reciprocating motion to said tool by Way of the swing system.

2. Motor driven working device in accordance with claim 1, Where for the purpose of mass balancing extra mass is added to the arm of the rocking lever and to said motor connecting rod.

3. Motor'd-riven working device in accordance with claim 1, where the magnitude of the lever arm defined by said motor connecting rod and the arm of s'aid'lever between'said motor connecting rod and the pivot point of said rocking lever is manually adju'stable.

4. Motor driven Working device in accordance with claim 1, Where means are provided for adjusting the magnitude of the lever arm of said rocking lever comprising said motor connecting rod and the lever arm between said rod and the pivot point, said means comprising a slot defined in said rocking lever generallycerit rally thereof, a toothed rack on said rocking lever proximate said slot and a pinion in engagement with said rack, said pinion having a shaft fixedly supported on said device and said shaft being adapted for engagement by a manual adjusting device.

5. Motor driven Working device in accordance with claim 2, where means are provided for adjusting the magnitude of the lever arm of said rockinglever comprising said motor connecting rod and the lever arm between said rod and the pivot point, said means comprising'a slot defined in said rocking lever generally centrally thereof, a toothed rack on said rocking lever proximate said slot, and a pinion in engagement with said rack, said pinion having a shaft fixedly supported on said device and said shaft being adapted for engagement by automatic adjusting means.

6. Motor driven working device in accordance with claim 2, where the magnitude ofthe lever arm defined by said motor connecting rod and the arm of said lever between said motor connecting rod and the pivot point of said rocking lever is manually adjustable.

References Cited UNITED STATES PATENTS 1 354,074 12/1886 Swan 74-40 2,499,473 3/1950 Elder 7433 2,548,807 4/1951 Morgan et a1. 74-40 2,877,652 3/1959 Muschalek 74-41 FRED C. MATTERN, 111., Primary Examiner.

WESLEY S. RATLIFF, Assistant Examiner. 

